<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../../react18/react.development.js"></script>
  <script src="../../react18/react-dom.development.js"></script>
  <script src="../../react18/babel.min.js"></script>
</head>

<body>
  <div id="app"></div>
  <script type="text/babel">
    /* 
      porps是用来做父子组件通信的
        - 在父组件中使用子组件的时候,可以给子组件添加属性
        - 在子组件中组件实例的props属性上,就能拿到这个属性和值
    
    */
    class Parent extends React.Component{
        state={
            car:'大众'
        }
        render(){
            const {car}=this.state
            return (
                <div>
                    <h1>我是父组件</h1>
                    <p>我开的车是{car}</p>
                    <button onClick={this.changeCarHandle}>change</button>
                    <hr/>
                    <Child a={1} car={car}/>
                    </div>
            )
        }
        changeCarHandle=()=>{
            this.setState({car:'奥迪RS7'})
        }
    }
      
    class Child extends React.Component{
        /* 
        当父组件更新状态的时候,子组件的render方法会重新执行生成新的虚拟DOM,也能拿到最新的props
      */
        render(){
            let {car}=this.props
            car='粉色的'+car
            return (
                <p>我是子组件，我开父组件的车{car+"！！！！！"}</p>
            )

        }
    }
    const root = ReactDOM.createRoot(document.getElementById('app'));
    root.render(<Parent/>)




  </script>
</body>

</html>